1 files changed, 57 insertions, 0 deletions
diff --git a/BSPTree.cpp b/BSPTree.cpp
index e7e6416..00e916b 100644
--- a/BSPTree.cpp
+++ b/BSPTree.cpp
@@ -1,5 +1,57 @@
 #include "BSPTree.h"
 
+#include <iostream>
+
+vmml::vec3f BSPTree::Plane::intersection(const vmml::vec3f &p, const vmml::vec3f &dir) const {
+  float r = (d - p.dot(normal))/dir.dot(normal);
+
+  return p + r*dir;
+}
+
+void BSPTree::Plane::partition(const Triangle &t, std::list<Triangle> *front, std::list<Triangle> *back) const {
+  for(int i = 0; i < 3; ++i) {
+    if(contains(t.getVertex(i))) {
+      const vmml::vec3f *v[3] = {&t.getVertex(i), &t.getVertex((i+1)%3), &t.getVertex((i+2)%3)};
+
+      vmml::vec3f is = intersection(*v[1], *v[2]-*v[1]);
+
+      if(isInFront(*v[1])) {
+        front->push_back(Triangle(*v[0], *v[1], is, t.getColor()));
+        back->push_back(Triangle(*v[0], is, *v[2], t.getColor()));
+      }
+      else {
+        back->push_back(Triangle(*v[0], *v[1], is, t.getColor()));
+        front->push_back(Triangle(*v[0], is, *v[2], t.getColor()));
+      }
+
+      return;
+    }
+  }
+
+  for(int i = 0; i < 3; ++i) {
+    const vmml::vec3f *v[3] = {&t.getVertex(i), &t.getVertex((i+1)%3), &t.getVertex((i+2)%3)};
+
+    if((isInFront(*v[0]) && isBehind(*v[1]) && isBehind(*v[2]))
+        || (isBehind(*v[0]) && isInFront(*v[1]) && isInFront(*v[2]))) {
+      vmml::vec3f is1 = intersection(*v[0], *v[1]-*v[0]);
+      vmml::vec3f is2 = intersection(*v[0], *v[2]-*v[0]);
+
+      if(isInFront(*v[0])) {
+        front->push_back(Triangle(*v[0], is1, is2, t.getColor()));
+        back->push_back(Triangle(is1, *v[1], is2, t.getColor()));
+        back->push_back(Triangle(*v[1], *v[2], is2, t.getColor()));
+      }
+      else {
+        back->push_back(Triangle(*v[0], is1, is2, t.getColor()));
+        front->push_back(Triangle(is1, *v[1], is2, t.getColor()));
+        front->push_back(Triangle(*v[1], *v[2], is2, t.getColor()));
+      }
+
+      return;
+    }
+  }
+}
+
 
 BSPTree::BSPTree(const std::list<Triangle> &triangles) : frontTree(0), backTree(0) {
   if(triangles.empty())
@@ -24,6 +76,11 @@ BSPTree::BSPTree(const std::list<Triangle> &triangles) : frontTree(0), backTree(
       back.push_back(*t);
       continue;
     }
+
+    std::list<Triangle> frontPart, backPart;
+    plane.partition(*t, &frontPart, &backPart);
+    front.splice(front.end(), frontPart);
+    back.splice(back.end(), backPart);
   }
 
   if(!front.empty())